Internal-combustion engine



Jan. 23, 1945.

s. R. ERICSQN 2,368,012

INTERNAL- COMBUSTION ENGINE Filed May 5, 1943 2 Sheets-Sheet l 7 24 V a 21 g 2 35 r: "p\.\ e 1 Qy 3 INVENTOR 2 Q 2 GEORGE R. ERICSON FiG.3. F|G.4. FIG.5. A RNEY Jan. 23, 1945. ERlcSQN 2568,1935

INTERNAL-COMBUSTION ENGINE Filed May 5, 1943 2 Sheets-Sheet 2 INVENTOR GEORGE R. ERICSON ATTORN EY Patented Jan. 23, 1945 IN TERNAL-COMBUSTION ENGINE George R. Ericson, Kirkwood, M0,, assignor to Carter Carburetor Corporation, St. Louis, Mo.,. a corporation of. Delaware Application May 5,1943, Serial No. 485,951

13 Claims.

This invention relates to internal combustion engines and particularly to automotive engines of the multicylinder type. The invention is an improvement of the devices shown in my earlier filed applications, Serial No. 453,116, filed July 31, 1942, and Serial No. 468,564, filed December 10, 1942.

In devices of the character shown in the previous applications, the fuel is cut off from some or all of the cylinders in accordance with the power requirements of the engine, as indicated. by the vacuum in the intake manifold. Cutting off the fuel in this way leaves one or more groups of cylinders without any fuel charge to produce power, but still operating to suck dry air through, a manifold past a partly closed throttle valve. This results in a considerable pumping loss and substantially increases the total motor friction. I have found that it. is possible to substantially'increase the fuel economy by leaving the air supply to one group of cylinders unthrottledand uncontrolled, so that the control valve for the fuel for that group of cylinders operates to set the cylinder group in full operation or to completely discontinue the production of power by that group.

In order to operate a cylinder group without a throttle, it is necessary to make the fuel control valve turn on or cut off completely and positively, so that the engine will never be supplied with a mixture which is too lean to fire steadily, but still containing enough fuel to pro duce an occasional backfire in the manifold or to cause surging by firing occasionally in the cylinder. control the fuel valve by a combination of suction and throttle position and incorporate an improved snap action mechanism which positively holds thevalve on its seat, or else positively holds it off. I control the snap action mechanism, so that. it will turn on the fuel in the auxiliary cylinder group when. the suction in the manifold leading to the main cylinder group falls to approximately 4 inches of mercury, but after it is once turned on the snap action valve remains open and keeps the auxiliary cylinder group in operation until the manifold vacuum in the main manifold has risen to approximately 12 or 15 inches of mercury; This enables the operator to find a. throttle position which will cause the engine to deliver substantially any desired torque. If the fuel inthe auxiliary cylinders were turned on at substantially the same manifold suction at which it was turned off, the driver would have In order tov meet this requirement, I

to be continually changing the throttle position to maintain the desired speed, especially when climbing a hill; else, the motor would start to hunt between the speedjust below and just above that at which the critical vacuum for operating the fuel valve is produced. Where: multicylinder engines have two gr ups of cylinders supplied by separate inanifolds, it is common practice to supply'hothn anifolds with fuel mixture from a. dual carburetor, having two throttles and two: sets of: venturis, nozzles. and accelerating pumps, but only one air inlet and one: choke. mechanism. I have found that such an arrangement does not give good. results where one throttle is omittedv and its barrel is to be run dry part of the time. I have found that better operation is to be obtained by completely separating the air inlets to the two mixing conduits. Theoperation during starting and warming up is still further improvedby using.

separate choke valves, controlled by different types of mechanism.

consideration of the following description, and accompanying drawings, in which Fig. 1 isa diagrammatic View of a carburetor, manifold, and a partial section of an eight cylinder motor.

Fig. 2 is a sectional diagram of a carburetor and manifold embodying my invention.

Fig. 3 is a sectional diagram showing a fuel control valve in closed position.

Fig. 4 is a sectional showing a fuel control valve in open position.

Fig. 5 is a sectional diagram showing a fuel. control valve in openposition but ready to be closed by the vacuum- Fig. 6 is a diagram of the automatic choke con-- trol used in the throttled barrel of the carburetor;

Fig- 7 is a diagram of the automatic choke control used in the unthrottledbarrel of the carburetor.

The reference character 1 indicates. the main. body casting of a carburetor, which is mounted on the riser flange Z of a dual intake. manifold having separate branches 3 and 4 leading: to the inner and outer cylinder groups of an. eight cylinder engine which is generally indicated at i;

The carburetor is provided with the usual fuel chamber 6, which is indicated to be of the constant level type, the level being maintained by float mechanism generally indicated at I. It may be noted that the fuel chamber may be of any type, and the fuel may be maintained under pressure if desired. The fuel is delivered from the float chamber through -.a calibrated metering passage 6 controlled by the metering rod 9 to a branched passage which leads to the main nozzle l6 and the idle port The main nozzle discharges into a conventional Venturi stack l2, and the idle passage discharges at the edge of the throttle valve |3, as is conventional in plain tube carburetor construction. The throttle is connected to the metering rod 6 by means of a one-way connection I5, and the metering rod, which is normally biased upwardly to the rich" position by a spring, is drawn downwardly by suction applied from below the throttle through the passage indicated at II. This construction is known to those skilled in the art, and for further details reference may be had to Patent Re. 21,610 to F. W. Cloedy et al. A throttle operated accelerating pump I8 is provided, for the purpose ofdelivering auxiliary charges of fuel through the nozzle |9.'

The carburetor so far described supplies fuel to the mixing conduit 26, which 'is connected to the outside intake manifold 4, and the outside cylinder group A is'thus constantly supplied with fuel during the operation of the motor. For starting purposes an unbalanced choke" valve 2| is mounted in the air inlet on the shaft 22, which is connected to an automatic choke control mechanism, preferably of the type shown in Coifey' Patent #2085351, or of the type shown in my previous Patent #1,915,851, it being noted that the choke position is the'resultant of three main forces, to wit, the temperature, the rate of air flow pastthe choke valve, and the suction posterior to the throttle.

The inside group of cylinders B is supplied with fuel mixture by the mixing conduit '23, which is provided with a .Venturi stack 24 similar to the stack in the mixing conduit 26. This mixing conduit is supplied with fuel from the same float chamber 6 as is the conduit 26, but the supply is intermittent, in accordance with the power re-' quired from the engine. No throttle is used'in conduit 23, and no idle port is provided. This side of the carburetor is eitherin full, wide open throttle operation, or i's'"'operated dry, without any fuel at all.

The fuel supplied to by the valve .25, and theposition of the valve is controlled by suction and throttle position. The suction operated piston 26, normally held in upward position by the'spring 21, may be drawn downwardly by suction from below the throttle, applied by means of a passage which is connected to the port 11. The valve 25 has a stem 26 provided at its upper end with a slot 29, and this is connected to the stem 36 of the piston 26 by means of the cross pin 3|. A finger 32 carried by the lever 33 underlies the cross pin 3|, and the lever 33 is pivoted to the carburetor body as at 34, so that the finger 32 is moved upwardly when the throttle valve I3 is opened.

The valve tem 26 i drilled to receive a spring 35, which is bent as indicated at 36 and 31 to slide over the hump" 36 in such a manner as I to cause the valve to be held either in its upper or its lower position, the bent portions 36 and a 81 are slightly different in height, and this arthe nozzle 24a is controlled rangement makes it practically impossible for the valve to retain a position in which it is nearly but not quite eated. The resiliency of the spring 21 contributes to the emciency of the snap action, as the valve cannot be displaced from its seat without the exertion of enough force to completely open it. p

In order to cause the fuel discharge to be started instantly when the valve 25 is opened, I mount a cylinder 39, containing a floating piston 46, at the base of the nozzle 24a. The piston is normally held in upward position by means of the pring 4|, but may be drawn downwardly by suction applied from below the throttle in the mixing conduit 26 through the conduit 42, which is connected to the port 43. The piston 46 is pro- I vided with a double expansible packing as shown,

so as to be leak-proof in both directions, and also to provide some friction. By thi arrangement the movement of the piston 46 may be substantially synchronized with the operation of the valve 25.

In order to provide for eiiicient cold starting,-

a choke valve 44 is mounted on an eccentric shaft 45 in the air inlet of the mixing conduit 23, and a thermostatic coil 46 is provided to close the choke when the temperature is low. This choke valve is independent of the suction below the throttle, and is moved toward open position against the action of the thermostat only by the direct action of the air flow. The heating means for warming up the thermostat is not shown, but may be the ame as shown in the previously mentioned Patents #2,085,351 or #1,915,851.

In operation, the engine is started on all eight cylinders, with the fullest possible chargesupplied to the central group of cylinders, but as soon as the engine begins to pick up speed, the vacuum in the outerintake manifold 4 is built up to about twelve or fifteen inches of mercury, which is sufllcient to draw the piston 26 downwardly against the spring 21, and cut off the fuel valve 25. The engine then continues to operate on the outside group of cylinders, which is supplied by the mixing conduit 26.

It will be understood that the valve |3 may be opened sufllcient for starting purposes without forcing the valve 25 open by means of the finger 32, but if the operator opens the throttle beyond approximately the one-third open position, the valve 25 is opened regardless of the suction which may exist in the outlet of the mixing conduit 23. After the valve 25 has been opened, it will remain open until the suction has been increased to approximately twelve inches of mercury, so that the operator may return the throttle to almost idle position before cylinder group B is cut out.

This arrangement enables him to find a throttle position to provide practically any amount of a housing 4! and carries arm 46 having an axially extending lip 46 and a curved extension terminating in a piston (not shown) siidable in a cylinder 5|, as described in the mentioned Coffey patent. Cylinder 5| connects to suction posterior to throttle |3 by means of a passage 52 (Fig. 2). A thermostatic coil 53 mounted in ing as and centrally fixed on choke shaft is. rue--- outer end of thecoilis hooked about a pin 55 on the housing Wall." Heat'is supplied through a passaged boss 51.

The exclusive use of all modifications as come within the scope of the appended claims is contemplated.

I claim:

1. In an internal combustion engine having a plurality of cylinder groups, separate intake conduits for supplying fuel mixture to said groups, a manually operated throttle valve for controlling the supply of fuel to one of said groups, the conduit supplying the other group of cylinders being unthrottled, a fuel valve for controlling the supply of fuel to said other group, and means responsive to the load demand on the engine for controlling said fuel valve.

2. In an internal combustion engine having a plurality of cylinder groups, separate intake conduits for supplying fuel mixture to said groups a manually operated throttle valve for controlling the supply of fuel to one of said groups, the conduit supplying said other group being unthrottled, a fuel valve for controlling the supply of fuel to said other group, and means responsive to pressure posterior to said throttle for controlling said fuel valve.

3. In an internal combustion engine having a plurality of cylinder groups, separate intake conduits for supplying fuel mixture to said groups,

a manually operated throttle valve for control-- ling the supply of fuel to one of said groups, the

conduit supplying said other group being unthrottled, a fuel valve for controlling the supply of fuel to said other group, means responsive to pressure posterior to said throttle for controlling said fuel valve, and means operated by said throttle for opening said fuel valve when said throttle is moved to fully opened position.

4. In an internal combustion engine having a plurality of cylinder groups, separateintake conduits for supplying fuel to said groups, separate fuel supply nozzles for supplying fuel to said conduits, a throttle valve for one of said conduits, the other conduit being unthrottled, a fuel valve for controlling the supply of fuel to said unthrottied conduit, and means controlled by said throttle for operating said fuel valve.

5. In an internal combustion engine having a plurality of cylinder groups, a separate fuel intake conduit for supplying each of said groups, a main fuel passage discharging into each of said conduits, a metering orifice in each of said passages, one of said conduits being unthrottled, and a throttle in the other conduit for regulating the supply of fuel to the engine.

6. In an internal combustion engine having a plurality of cylinder groups, a separate fuel intake conduit for supplynig each of said groups, a main fuel passage discharging into each of said conduits, a metering orifice in each of said passages, one of said conduits being unthrottled, and

' a throttle in the other conduit for regulating the flow of fuel through both conduits.

7. In an internal combustion engine having a plurality of cylinder groups, a separate fuel intake conduit for supplying each of said groups. a main fuel passage discharging into each of said 1 controlling the=supply of fuel therethrough i and means to control said valve in accordance -witb-:; thepositioncream-throttle.- 4-,;

851d an internal combustion engine having; a pli irality of cylindergroups, .aseparaterfuel .l-nesictake conduit for supplying each of said groups, a main fuel passage discharging into each of said conduits, a metering orifice in each of said passages, one of said conduits being unthrottled, a valve controlling the metering orifice on said unthrottled side, a throttle in the other conduit controlling the supply of fuel therethrough, and means to control said valve in accordance with suction posterior to said throttle.

9. In an internal combustion engine having a. plurality of cylinder groups, a separate fuel intake conduit for supplying each of said groups, a main fuel passage discharging into each of said conduits, a metering orifice in each of said passages, one of said conduits being unthrottled, a valve controlling .the metering orifice on said unthrottled side, a throttle in the other conduit controlling the supply of fuel therethrough, and means to control said valve in accordance with the position of said throttle, and tosupply an extra charge of fuel to said unthrottled conduit upon opening of said valve.

10. In an internal combustion engine having a plurality of cylinder groups served by separate intake ducts, means forming a throttled mixing conduit for supplying fuel to one of said ducts, means forming an unthrottled mixing conduit for supplying fuel to the other intake duct, valve means for controlling the supply of fuel to said unthrottlecl mixing conduit, a manually operated throttle for said throttled mixing conduit, means controlled by vacuum posterior to said throttle for actuating said fuel valve, and means resisting the final closing and initial opening movements of said valve.

11. In an internal combustion engine having a plurality of cylinder groups served by separate intake conduits, means forming a throttled mixing conduit for supplying fuel to one of said conduits, means forming an unthrottled mixing conduit for supplying fuel to the other intake conduit, valve means for controlling the supply 01' fuel to said unthrottled mixing conduit, a manually operated throttle for said throttled mixing conduit, means controlled by vacuum posterior to said throttle for actuating said fuel valve, and means resisting the final closing and initial opening movements of said valve, said valve actuating and resisting means being constructed and arranged to cause said valve to remain in closed position until the vacuum has fallen to a comparatively low value, but to caus said valve to remain in open position after it has once been opened until the vacuum rises to a substantially higher value.

12. In an internal combustion engine having a plurality of cylinder groups, separate mixing conduits supplying fuel to said groups, a throttle for one of said mixing conduits, the other conduit being unthrottled, an unbalanced choke valve mounted in the throttled inlet, heat responsive means tending to close said choke valve, and means responsive to suction posterior to the throttle tending to open said choke valve, a sec-' and choke valve in the unthrottled conduit, and heat responsive means tending to hold said sec- 

